Unit 3The Earth – Moon – Sun

SystemVocabulary

Review

the periodic rise and fall of the water levels in the oceans

and other large bodies of water

tide

the time required for Earth to rotate once on its axis

day

a tide of increased range that occurs two times a month, at the

new and full moons

spring tide

the time required for Earth to orbit once around the sun

year

the point at which the sun is as far north or as far south of the equator as possible; the area of sunlight is

at maximum in one hemisphere and at minimum in the other

solstice

the outer part of a shadow such as the shadow cast by the Earth

or moon in sunlight is only partially blocked

penumbra

the force of attraction between two objects that is due to their

masses

gravity

the motion of a body that travels around another body in space; one complete trip along

an orbit

revolution

a natural or artificial body that revolves around a celestial body

that is greater in mass

satellite

a tide of minimum range that occurs during the first and third

quarters of the moon

neap tide

the moment when the sun appears to cross the celestial equator; sunlight shines equally on the

northern and southern hemispheres

equinox

the difference in levels of ocean water at high and low

tides

tidal range

an event in which the shadow of one celestial body falls on

another

eclipse

the different appearances of the of the moon from Earth throughout

the month

lunar phase

a division of the year that is characterized b recurring weather

conditions and determined by both Earth’s tilt relative to the sun Earth’s position in its orbit around the sun

season

a shadow that blocks sunlight; such as the conical section in

the shadow of Earth or the moon

umbra

the spin of a body on its axis

rotation